Papers by Keyword: Concentration

Abstract: Water is a necessary element that is useful for survival of human being, animal and plants. Water exists as streams, rivers, lakes and oceans. Naturally, it is observed that overtime the volume of water that exists in the natural reservoirs of streams and rivers reduces due to inflow of sands, stone, debris and other sediments in the water. This sediment yield and concentration if not properly managed reduces water volume thereby causing scarcity. Modeling the sediment yield, sediment concentration in River Idemili in Anambra State is necessary to determine the rate and quantity of sediment inflow into the river so as to proffer solution on how to reduce the sediment inflow and solve water scarcity. The tools used for the modeling are GIS, Land use, soil maps and climate data such as temperature, humidity, rainfall data etc. The data were imputed into the MAPWINDOW GIS to analyze and predict sediment yield and concentration in River Idemili from the period of 1999 to 2021. Results from the analysis reveals that there are nine sub-basin in the catchment area. River Idemili falls within sub-basin 5 and 6. Result shows that maximum yield in the sub-basin are 23.3686t/ha and the maximum sediment concentration in the Idemili River stand at 38.709mg/c. Controling the sediment yield and concentration, the indiscriminant falling of trees, aggressive removing of vegetative cover should be reduced so that soil surface are not exposed to erosion that will carry the loose soil, silt and plant remains into the River Idemili.

Abstract: The FeCl₃.6H₂O synthesis process into Fe₃O₄ uses the Green Synthesis method by adding NaOH from FeCl₃.6H₂O solution to pineapple leaf extract (Ananas Comosus). Pineapple leaf extract obtains hydroxyl and carbonyl, which serve as production agents for the synthesized FeCl₃.6H₂O. Extraction is done using the boil method to extract pineapple leaves. The concentration of FeCl₃.6H₂O in the synthesis is a factor in forming Fe₃O₄. In the manufacture of Fe₃O₄ nanoparticles, variations in FeCl₃.6H₂O concentration were given, namely 0.1 M, 0.5 M, and 1 M. From the results of Fourier Transfrom Infrared Spectroscopy (FTIR) testing on pineapple leaves; it was proven that carbonyl and hydroxyl groups were present. For the results of X-Ray Diffraction (XRD) testing, it is proven that the formation of Fe₃O₄. For Scanning Electron Microscope-Energy Dispersive X-ray (SEM-EDX) testing, the optimum variation is 0.5 M because it has an average particle size of 220.31 nm with an irregular particle shape. Then in Surface Area Analyzer (SAA) testing, the surface area is 28.782 m²/g. The highest percent degradation results of each variation that contacted with methylene blue (MB) is a concentration of 0.1 M with a contact time of 60 minutes base on Ultraviolet–visible spectroscopy (Uv-Vis) data.

Abstract: Water-soluble cutting fluids are routinely used as coolants and lubricants in the metalworking process. The properties of these water-soluble cutting fluids change during operation. In the management of the properties of water-soluble cutting fluids, it is crucial to maintain the concentration within an appropriate range. In typical manufacturing facilities, the concentration of water-soluble cutting fluids is measured using Brix. The commonly used Brix meters are of the sampling type. However, measuring the concentration of cutting fluids in numerous machine tools can be time-consuming. In addition, there has been a recent demand for automated measurement and management of concentration and data accumulation. In recent years, relatively inexpensive automatic Brix meters have become available in Japan. In this study, we tried to continuously measure the concentration of water-soluble cutting fluids using an automatic Brix meter. We installed an automatic Brix meter in a tank that continuously circulates 40L of water-soluble cutting fluid and measured it for several tens of days, confirming that it can measure stably. However, depending on the type of water-soluble cutting fluid, the measurement results may become unstable immediately after starting the measurement. Therefore, it was found that the choice of the water-soluble cutting fluid to be used is also important for the concentration measurement by the automatic Brix meter.

Abstract: The oscillations presence of the substance condensed state parameters and the n-alkanes combustion process was analyzed. It is shown that the smallest substance structural unit that describes such features is a dimer, a hexamer for methane, and a trimer for ethane. The cluster "equivalent length" based on the framework number atoms in the continuous chain and without taking into account cluster side parts was used as a modulating parameter. Attention was drawn to the dependences similarity for water solubility and the autoignition temperature of n-alkanes. It is proposed to take into account clustering involving water molecules for the water solubility, and oxygen molecules in the peroxide groups form that form similar clusters for combustion processes. It is accepted that the solubility limit is determined by the condition of all water molecules aggregation by the substance, and in combustible mixtures the substance aggregates all available oxygen in the air. Corresponding peroxide proportions allow the burning limits, detonation limits, stoichiometric concentration and cold flame limit to be described. An approximation formula has been developed that describes the general dependence of the n-alkanes and 2-methylalkanes autoignition temperature based on values of the cluster length and the monomer molecular weight.

Abstract: In the fabrication of fuel cell electrodes, applying catalyst ink onto a substrate is crucial. The performance of the proton exchange membrane fuel cell (PEMFC) is subsequently impacted by how the catalyst is applied onto substrate as well as in terms of its resulting morphology. In this study, a direct catalyst ink spraying approach was done in order to investigate transfer efficiency and surface morphology for different concentrations of ink. The concentration of catalyst ink used in the spraying process are 0.5, 1.0, 1.5, 2.0 and 2.5 mg/ml with fixed loading of 1.0 mg/cm². The transfer efficiency of the catalyst inks was calculated neglecting human error during spraying. The coating thickness and distribution of the resulting catalysts were analysed via Field Emission – Scanning Electron Microscope (FESEM).

Abstract: The main aim of this work is to develop an automated system for sample preparation. For the detection of small amounts of biological material, methods and procedures for concentration must be used. In this case, sample preparation refers to the concentration of bacteria in solutions. The problem of automated concentration of microbiological substances of low concentration in solution is discussed in more detail in this work. During sampling, volumes of approximately 100 mL are taken and processed. To achieve this goal, the construction of an automated system was planned and implemented. This system without contamination of the sample was implemented using a peristaltic pump, pinch valve, and air bubble detector. The influence of different system parameters has been investigated and the function of the system was tested for suitability in laboratory experiments. In addition, results from laboratory tests were evaluated. It was shown that a concentration of samples is possible with the help of a filter and backwash process. From this it is evident that an automated setup for this process should be aimed at, to make the procedure possible for non-specialized personal in this field. Furthermore, human error should additionally be minimized compared to all manual laboratory test. This study demonstrates such a system and shows the potential of filtering and backwashing of bacteria.

Abstract: Pluronic P123 has become a potential agent for solubilizing various metal oxide precursor molecules. However, how these solubilizates affect the morphology of material remains poorly understood. In this review, the morphological transition of TiO₂ and Fe₂O₃ induced by Pluronic P123 micelles has been comprehensively investigated. The change of TiO₂ and Fe₂O₃ structure by P123 micelles forms micellar clusters governed by the balance of hydrophobic interaction and hydrogen bonding, which consequently leads to various micellar morphologies. The review results further show that the intensity of P123-TiO₂ and and P123-Fe₂O₃ interaction increases with the hydrophobicity of the P123, indicating that hydrophobic interaction is more important in the TiO₂ and Fe₂O₃ morphological transition. The transformation of the disordered morphology is more effective in the acidic pH scale range than the basic and neutral ones. Not only pH, but also seen when the reaction time not more than 4 hours with moderate temperature ranging from 300-500 °C and the ratio of P123 to Ti and Fe precursors of 1-5% (%w/w) is the optimum condition which changes the disordered morphology to a more regular one. The acidity, time reaction and temperature as the main parameter influencing the enhancement of the physical properties and morphology for the considered reaction.

Abstract: There is a lack of information on the magnetic properties of particles of such materials as powder magnetic (modified by inclusions of magnetite and maghemite) carbon sorbents intended for water purification from various kinds of impurities and, what is especially important, allowing to perform the prompt isolation of the spent sorbent – by magnetic separation. The data on the magnetic susceptibility χ of the particles of these sorbents, found by the developed experimental calculation method based on the concept of the corresponding magnetometry of a moderately rarefied dispersed sample with a dispersed phase of the particles under study, are presented. Experimental dependences of the magnetic susceptibility of <χ>of a dispersed sample on the volume fraction γ of controlled particles in it have been obtained - for different values ​​of the magnetic field strength H in the range from 22 to 61 kA/m, i.e. in the postextremal region for the susceptibility. In addition to the necessary assessment of their linear, located at γ ≤ 0.15-0.2, sections, this also made it possible to find and phenomenologically describe the field dependences of the generalized data of the reduced susceptibility of <χ>/γ, i.e. data χ: in the form of an inverse power function with a power of 0.7 ... 0.8 at H.

Abstract: Armyworm (Spodoptera frugiperda) is a pest on several food crops including soybeans and corn. Armyworm control still emphasizes the use of resistant varieties and insecticides. Alternative efforts are needed to use more environmentally-friendly control methods, including the use of organic pesticides from biological materials. The control of Spodoptera frugiperda was carried out by testing the application of several types of organic pesticides at the same concentration of 50%. The purpose of this study was to determine the type of pesticide that was most effective in reducing mortality and attack from Spodoptera frugiperda. The study was started by doing mass propagation of S. frugiperda larvae, S. frugiperda larvae investment, and mortality test. The test used the Randomized Block Design (RBD) method using several organic pesticides consisting of five treatments, namely P0 (control), P1 (tobacco), P2 (shallot), P3 (garlic), and P4 (papaya leaves), P5 (blimbing wuluh leaves), P6 (Jatropa curcas fruit), P7 (lemongrass). The results of the application of organic pesticides on the mortality and attack rate of S. frugiperda had a significant effect. Organic pesticides that are most effective in reducing the mortality and attack rates of S. frugiperda are pesticides made from tobacco (Nicotiana tabacum). At a concentration of 50% organic pesticides made from tobacco can reduce the mortality of S. frugiperda up to 100%. Tobacco-based pesticides also received the lowest land attack rate at 46%. Organic pesticides applied to S. frugiperda larvae also affect the growth of S. frugiperda pupae.

Abstract: In the work, a variant of mathematical modeling of the solution of the heat transfer problem was developed, analytical analysis of the dependencies of the parameters of technological parameters was carried out to determine the parameters of current pulses that ensure a uniform distribution of current density over the treated surface. A diagram of the stages of constructing a complete mathematical model of the ECDP process (electrochemical dimensional processing) of titanium, aluminum, and their alloys is given. The above equations reflect the theory of mass transfer processes, include the temperature parameter. The limitations of the possibility of carrying out the treatment process are modeled, the peculiarities of formation and development of the gas-liquid layer, changes in its physical properties, and violation of the treatment stability are taken into account. It has been found that to eliminate the processing instability associated with the appearance of turbulence in the electrode reaction zone due to the large gas filling of the interelectrode gap, a series of relationships must be considered DT = f (i, Q, t_imp) to determine optimal parameters of pulse current.